The present invention is generally directed to hearing protectors and is specifically directed to an earmuff type hearing protector including an electronic circuit for enabling the wearer to hear audio waves at a non-harmful volume level.
It is necessary for persons engaging in activities within high volume sound environments to wear hearing protectors, such as earmuffs, in order to protect their hearing. Hearing protectors of this type have proven to be particularly beneficial to persons working around jet aircraft or shooting on a practice range, for example.
However standard earmuffs that are effective in significantly reducing the volume of ambient sound waves transmitted directly to the wearer's ears from the environment so as to protect the ears from loud harmful noises also usually prevent the wearer from hearing words spoken by another person in his vicinity. One solution to this shortcoming of standard earmuffs was suggested by Ball Corporation, Muncie, Indiana in an advertisement for an "automatic gain controlled hearing protector". Such hearing protector is an earmuff type protector which was described as "an audio instrument which protects hearing and improves voice intelligibility in high noise environments. A microphone senses surrounding sound, filters out potentially harmful frequencies, and passes on only those frequencies pertinent to the human voice range". However, such hearing protector has not been made commercially available notwithstanding such advertisment.
It is the object of the present invention to provide a commercially practical hearing protector of the earmuff type having an electronic circuit for enabling the wearer to hear audio sound waves within a predetermined frequency range and at a non-harmful volume level. In this regard the electronic circuit of the earmuff should include a control circuit of simple and economical construction for automatically limiting the volume of the sound waves produced by the speaker when the level of the signal to the speaker increases.